Filtering digital images and video frames to reduce noise without destroying textures and fine structures depicted therein is often a de facto component of the image processing for many applications. One example of such an application, but by no means the only example, is in the field of electron cryomicroscopy.
Electron cryomicroscopy is a remarkable technology enabling new discoveries at sub-cellular scale. Studies at such scale aim to understand the structure and function of the macromolecular machinery responsible for regulating cell mechanisms with the ultimate goal of transforming living cells to attain desired configurations and perform specific tasks, such as, cure diseases and transform plants into fuel.
Researchers rely on pictures of samples maintained at cryo (freezing) temperatures to investigate a particular cell type in its near native state. A picture of a cell is formed after a beam of electrons is projected through the sample and captured by a charged-coupled device (CCD) camera. Due to a low dosage of electrons, necessary to avoid damaging the thin biological sample, a poorly resolved, noisy, low contrast image is formed. In the case of cryotomography, a series of unfiltered 2D projections are combined to build a 3D reconstruction of the cell. In this process, noise is transferred to the reconstructed object.